1. Field of the Invention
The present invention relates to a valve gear device for internal combustion engines.
2. Description of the Related Art
As the related art of the valve gear device for internal combustion engines in the present invention, Japanese Unexamined Patent Publication No. 94,405/1992 (Kokai) discloses a variable valve timing device. As shown in FIG. 5, this variable valve timing device comprises: a high-speed cam low-speed cams 72 and 73 which are provided at both sides of the high-speed cam and a cam shaft 70 to which the low-speed cams 72 and 73 and the high-speed cam 71 are fixed. This device further comprises: a guide 74 which is buried in the cylinder head (not shown) of internal combustion engines; a body 76 which is provided so as to slide freely in the inner peripheral hole 75 of the guide 741 and a slider 77 which is provided so as to slide freely in the body 76. This slider may be constituted in either of the following states: this slider 77 is able to move relatively to the body 76 or this slide is not able to move relatively to the body 76. Furthermore, the body 76 has a detent 78. This detent 78 prevents the body 76 and the guide 74 from rotating relatively to each other. At the top of the guide tube 74, a groove 79 is formed so as to avoid the interference of the high-speed cam 71 and the groove 80 (only the groove for the low-speed cam 72 is shown) is also formed there so as to avoid the interference of the low-speed cams 72 and
In this device, the slider 77 is in the shape of cylinder and the top surface of the slider 77 is in the shape of a circle. The diameter of the top surface of the slider 77 is larger than the width of the high-speed cam 71. The contacting surface of the body 76 which is driven by the low-speed cams 72 and 73 should necessarily be located at the outer peripheral side of the slider 77. As the result, the outer peripheral diameter of the body 76 is inevitably enlarged and this has caused to prevent the whole device from being miniaturized.